[RFI] Power Line Noise

Michael Martin, RFI Services mike at rfiservices.com
Thu Apr 16 18:25:59 EDT 2020

Another observation I'd like to share.
I commonly find powerline noise sources on poles in front of ham's homes that are very high in level but have no effect on their HF reception.
Often I find from the ham to the source as many as 10 to 15 power line noise sources before I get to the one that's affecting the ham.

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Michael Martin

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On Apr 16, 2020, 6:16 PM, at 6:16 PM, K9MA <k9ma at sdellington.us> wrote:
>On 4/16/2020 17:02, AA5CT wrote:
>> re: "I went out today to track down a noise source, which on the
>> HF bands appears to be coming from the east. "
>> Scott, I give you even money odds that you found ANOTHER noise
>> source on VHF, and not the one that was affecting you on HF (unless
>> you already got it fixed, and that was it, in which case I lose hi
>I doubt it. This source is just too incredibly loud at 135 MHz and
>(maybe 300 feet from the antenna) that it can't possibly NOT be causing
>HF interference. I agree with your point, though. When tracking at VHF,
>I always hear lots of sources that are not the one causing the HF 
>problem. I deal with that by relaying the noise from the HF receiver at
>home so that I can hear it while I'm out tracking. There is always a 
>pattern to the fluctuations. When I find that they match, I know I've 
>got the right source. This is the same principle as taking the "noise 
>signature", without the expensive equipment. It has served me well.
>I didn't bother this time because the source is so ridiculously strong 
>on VHF right out my front door.
>Scott K9MA
>Scott  K9MA
>k9ma at sdellington.us
>RFI mailing list
>RFI at contesting.com

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